Understanding and Using American Community Survey Data What Researchers Need to Know Issued March 2020 Acknowledgments Linda A. Jacobsen, Vice President, U.S. Programs, Population Reference Bureau (PRB), and Mark Mather, Associate Vice President, U.S. Programs, PRB, drafted this handbook in partnership with the U.S. Census Bureau’s American Community Survey Office. Other PRB staff who assisted in drafting and reviewing the handbook include Beth Jarosz, Lillian Kilduff, and Paola Scommegna. Some of the material in this handbook was adapted from the Census Bureau’s 2009 publication, A Compass for Understanding and Using American Community Survey Data: What Researchers Need to Know, drafted by Warren A. Brown. American Community Survey data users who provided feedback and case studies for this handbook include Jean D’Amico, Brett Fried, and Sarah Kaufman. Nicole Scanniello, Gretchen Gooding, and Charles Gamble, Census Bureau, contributed to the planning and review of this handbook series. The American Community Survey program is under the direction of Albert E. Fontenot, Jr., Associate Director for Decennial Census Programs, James B. Treat, Assistant Director for Decennial Census Programs, and Donna M. Daily, Chief, American Community Survey Office. Other individuals from the Census Bureau who contributed to the review and release of these handbooks include Grace Clemons, Barbara Downs, Justin Keller, Amanda Klimek, R. Chase Sawyer, Michael Starsinic, and Tyson Weister. Linda Chen, Faye E. Brock, and Christine E. Geter provided publication management, graphics design and composition, and editorial review for print and electronic media under the direction of Janet Sweeney, Chief of the Graphic and Editorial Services Branch, Public Information Office. Understanding and Using American Community Survey Data Issued March 2020 What Researchers Need to Know U.S. Department of Commerce Wilbur Ross, Secretary Karen Dunn Kelley, Deputy Secretary U.S. CENSUS BUREAU Steven Dillingham, Director Suggested Citation U.S. Census Bureau, Understanding and Using American Community Survey Data: What Researchers Need to Know, U.S. Government Printing Office, Washington, DC, 2020. U.S. CENSUS BUREAU Steven Dillingham, Director Ron Jarmin, Deputy Director and Chief Operating Officer Albert E. Fontenot Jr., Associate Director for Decennial Census Programs James B. Treat, Assistant Director for Decennial Census Programs Donna M. Daily, Chief, American Community Survey Office Contents 1. Topics Covered in the ACS ............................................1 2. How Researchers Use ACS Data .......................................3 3. Sampling Error in the ACS ...........................................12 4. Other Considerations in Working With ACS Data .......................15 5. Case Studies Using ACS Data. 18 6. Additional Resources ................................................32 Understanding and Using American Community Survey Data iii U.S. Census Bureau What Researchers Need to Know iii This page is intentionally blank. UNDERSTANDING AND USING AMERICAN COMMUNITY SURVEY DATA: WHAT RESEARCHERS NEED TO KNOW The American Community Survey (ACS) is the nation’s over a period of time rather than for a single point in premier source of detailed social, economic, housing, time as in the decennial census, which is conducted and demographic characteristics for local communities. every 10 years and provides population counts as of April 1 of the census year. This handbook describes how researchers can use ACS data to make comparisons, create custom tables, and ACS 1-year estimates are data that have been col- combine ACS data with other data sources. It is aimed lected over a 12-month period and are available for at researchers who are familiar with using data—sum- geographic areas with at least 65,000 people. Starting mary tabulations and microdata records—from com- with the 2014 ACS, the Census Bureau is also produc- plex sample surveys. ing “1-year Supplemental Estimates”—simplified ver- sions of popular ACS tables—for geographic areas with at least 20,000 people. The Census Bureau combines What Is the ACS? 5 consecutive years of ACS data to produce multiyear The ACS is a nationwide survey designed to provide estimates for geographic areas with fewer than 65,000 communities with reliable and timely social, economic, residents. These 5-year estimates represent data col- housing, and demographic data every year. A sepa- lected over a period of 60 months.1 rate annual survey, called the Puerto Rico Community Survey (PRCS), collects similar data about the popula- For more detailed information about the ACS—how tion and housing units in Puerto Rico. The U.S. Census to judge the accuracy of ACS estimates, understand- Bureau uses data collected in the ACS and the PRCS ing multiyear estimates, knowing which geographic to provide estimates on a broad range of population, areas are covered in the ACS, and how to access ACS housing unit, and household characteristics for states, data on the Census Bureau’s Web site—see the Census counties, cities, school districts, congressional districts, Bureau’s handbook on Understanding and Using census tracts, block groups, and many other geo- American Community Survey Data: What All Data Users graphic areas. Need to Know.2 The ACS has an annual sample size of about 3.5 million 1 The Census Bureau previously released 3-year estimates based on 36 months of data collection. In 2015, the 3-year products were discon- addresses, with survey information collected nearly tinued. The 2011–2013 ACS 3-year estimates, released in 2014, are the every day of the year. Data are pooled across a calen- last release of this product. dar year to produce estimates for that year. As a result, 2 U.S. Census Bureau, Understanding and Using American Community Survey Data: What All Data Users Need to Know, <www.census.gov ACS estimates reflect data that have been collected /programs-surveys/acs/guidance/handbooks/general.html>. 1. TOPICS COVERED IN THE ACS The primary purpose of the American Community • Economic characteristics include employment sta- Survey (ACS) is to help Congress determine funding tus, health insurance, income, and earnings. and policies for a wide variety of federal programs. Because of this, the topics covered by the ACS are • Examples of housing characteristics include com- diverse (see Table 1.1). puter and Internet use, selected monthly owner costs, rent, and the year the structure was built. • Examples of social characteristics include disability, educational attainment, language spoken at home, • Demographic characteristics include age, sex, race, and veteran status. Hispanic origin, and relationship to householder. Understanding and Using American Community Survey Data 1 U.S. Census Bureau What Researchers Need to Know 1 Table 1.1. Population and Housing Data Included in the American Community Survey Data Products Social Characteristics Economic Characteristics Plumbing Facilities6 Ancestry Class of Worker Rent Citizenship Status Commuting (Journey to Work) Rooms/Bedrooms Disability Status1 Employment Status Selected Monthly Owner Costs Educational Attainment Food Stamps/Supplemental Telephone Service Available Fertility Nutrition Assistance Program Tenure (Owner/Renter) (SNAP)4 Grandparents as Caregivers Units in Structure Health Insurance Coverage2 Language Spoken at Home Value of Home Income and Earnings Marital History2 Vehicles Available Industry and Occupation Marital Status Year Householder Moved Into Place of Work Migration/Residence 1 Year Ago Unit Poverty Status Period of Military Service Year Structure Built Work Status Last Year Place of Birth School Enrollment Demographics Characteristics Housing Characteristics Age and Sex Undergraduate Field of 5 Degree3 Computer and Internet Use Group Quarters Population Veteran Status2 House Heating Fuel Hispanic or Latino Origin Year of Entry Kitchen Facilities Race Occupancy/Vacancy Status Relationship to Householder Occupants Per Room Total Population 1 Questions on Disability Status were significantly revised in the 2008 survey to cause a break in series. 2 Marital History, Veterans’ Service-Connected Disability Status and Ratings, and Health Insurance Coverage were added in the 2008 survey. 3 Undergraduate Field of Degree was added in the 2009 survey. 4 Food Stamp Benefit amount was removed in 2008. 5 Computer and Internet Use was added to the 2013 survey. 6 One of the components of Plumbing Facilities, flush toilet, and Business or Medical Office on Property questions were removed in 2016. Source: U.S. Census Bureau. useful for novice users who want to explore the range TIP: The ACS was designed to provide estimates of of topics that are available.5 Copies of ACS question- the characteristics of the population, not to provide naires for different years are also available on the counts of the population in different geographic areas Census Bureau’s Web site.6 or population subgroups. For basic counts of the U.S. population by age, sex, race, and Hispanic origin, For more detailed information about the topics in visit the Census Bureau’s Population and Housing Unit the ACS, see the section on “Understanding the ACS: Estimates Web page.3 The Basics” in the Census Bureau’s handbook on Understanding and Using American Community Survey A good way to learn about all of the topics covered in Data: What All Data Users Need to Know.7 the ACS is to explore the information available through the U.S. Census Bureau’s data dissemination platform 4 on data.census.gov. The Data